The present invention relates to the field of networking data devices, and more particularly to an adaptive networking device for enhancing performance of a hybrid networking system.
Ethernet is a shared-media network architecture defined in the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard, and is currently the most widely used architecture for local-area networks (LANs). Ethernet uses both bus and star topologies having nodes attached to a trunk segment, which is the main piece of cable in an Ethernet network. The 10Base-T is a communication protocol based on the IEEE 802.3 standard, which is a baseband 802.3-based Ethernet network that operates up to 10 Mbps (megabits per second), and uses unshielded twisted-pair (UTP) cable configured in a star topology. The 10Base-T protocol is also known as twisted-pair Ethernet or UTP Ethernet.
Another Ethernet standard has emerged, referred to as fast Ethernet or 100Base-T Ethernet, which includes implementations capable of 100 Mbps transmissions speeds over UTP or shielded twisted-pair (STP) and is defined in IEEE 802.3u. 100Base-T covers several physical media types, including 100Base-T4 and 100Base-TX using twisted-pair wires. Twisted-pair Ethernet networks typically use RJ-45 modular connectors or variations thereof. Other mediums are known, such as 10Base-F for fiber-optic cable, including fiber passive (FP), fiber link (FL) and fiber backbone (FB). Networks using fiber optic media operate in a similar manner as twisted-pair, but include appropriate fiber-optic cabling, connectors, and physical media interface devices.
Each node in the network is typically a computer of some type, such as a personal computer (PC), minicomputer, mainframe, or the like, where the computer generally includes a network interface card (NIC) for interfacing the computer to a network device, such as a hub, concentrator, repeater, router, bridge, switch, etc., to enable networking capabilities. In the present disclosure, each node or segment is associated with a network device or data terminal equipment (DTE), where each generally refers to any source or destination of data connected to any network system, such as a LAN or the like.
A network operating according to a given communications protocol may be expanded by using one or more repeaters. A repeater is a hardware device that functions at the physical layer of the Open Systems Interconnection (OSI) Reference Model and includes several ports to connect two or more segments of the same network. In particular, a repeater receives packets or data from a node coupled to one port and re-transmits the packets or data to nodes attached to the other ports of the repeater. For example, a 10 Mbps repeater in a star configuration with six ports receives a data packet on one of its ports and repeats or re-transmits the message to the remaining five ports. One particular disadvantage of repeaters is a significant amount of extraneous data traffic, since data is repeated to all nodes even though usually intended for only one or a subset of the nodes.
A bridge is a hardware device which passes packets from one network to another. Bridges operate at the data-link layer of OSI Reference Model and makes several networks appear as a single network to higher level protocols or programs. A bridge serves both as a medium and as a filter, and it allows packets from a node on one network to be sent to a node on another network. At the same time, the bridge discards any packets intended for the originating network rather than passing these to the other network. A switch is a device that connects information coming in with an appropriate outlet. For example, the input may be packets and the outlet might be an Ethernet bus, such as in an Ethernet switch. A switch is similar in function to a multi-port bridge.
The advent of the 100 Mbps standard and a corresponding transition in the industry towards higher transmission rates often results in hybrid systems that service both 10 Mbps and 100 Mbps data devices. One particular product is the 28115 10/100 Ethernet Switch by Bay Networks. The 28115 switch has 16 ports, each capable of operating at 10 Mbps or 100 Mbps switched. This particular product is relatively expensive since each port is capable of operating at 100 Mbps, where the port is simply throttled back when coupled to a 10 Mbps device. A device which is capable of switch functions at 100 Mbps is very expensive. Also, if several slower speed devices are connected to a single high speed device, such as a server, much of the high speed switch capability is wasted, resulting in an inefficient design.
As networks have evolved with a mix of data devices operating at different communication rates, hardware typically has to be modified and upgraded. It is desired to provide hybrid operation and to enable modifications or upgrades in a cost effective manner.
An adaptive networking device according to the present invention includes a plurality of network ports operable at any one of a plurality of media standards, a bus, and a first device coupled to the bus that communicatively couples to any of the network ports that operate at a first media standard in order to transfer data between the bus and network ports communicatively coupled to the first device. The adaptive networking device further includes a second device operable at a second media standard and including a link port, where the second device communicatively couples to any of the network ports that operate at the second media standard to transfer data between the link port and those network ports communicatively coupled to the second device. The adaptive networking device further includes a bridge that transfers data between the link port and the bus to enable communication between the first and second devices.
In an embodiment described herein, the first device operates as a network switch, the second device operates as a network repeater and the bridge operates as a switch for filtering communication between the link port and the bus. Each of the network ports includes media circuitry that detects a node coupled to a corresponding port and determines the media standard of the node. The media circuitry communicatively couples the corresponding network port to one of the first and second devices based on the determined media standard. In this manner, a network node that operates at the first media standard and that is coupled to the adaptive networking device via a network port is placed into a switched domain whereas a network node that operates at the second media standard is placed into a shared domain. The bridge enables communication between the switched and shared domains without substantially affecting the performance of either domain. In an embodiment described herein, the first media standard is 10BaseT Ethernet(trademark) operating at 10 megabits per second (Mbps) and the second media standard is 100BaseTX operating at 100 Mbps. The bus is implemented according to the Peripheral Component Interconnect (PCI) standard and operates at a data transmission rate of approximately one gigabit per second (Gbps). The bridge preferably includes a second link port that operates as an uplink port for the adaptive networking device. The uplink port enables expansion of either one of the switched and shared domains. A management device may be coupled to the bus and the second device to provide management functionality. A memory device may also be provided and coupled to the management device.
The present invention contemplates the use of network components commercially available. In an alternative embodiment, the first device may instead be a plurality of switch modules coupled to the bus, where each couples to a respective subset of the network ports. Also, the second device may instead be first and second repeater modules, each coupled to respective first and second sets of the network ports. For example, the adaptive networking device may include 24 ports, where three switch modules handle eight ports each and two repeater modules handle 12 ports each. The switch modules each include bus interfaces for communicatively coupling to the bus. The bridge includes a bus interface for communicatively coupling to the bus and a MAC port for communicatively coupling to a corresponding MAC port of one of the repeater modules.